Pulsating multi-pipe heat pipe

ABSTRACT

A pulsating multi-pipe heat pipe has its pipe bodies arranged in parallel and bent into a plurality of snake-shaped metal pipes, and an independent chamber is furnished respectively at both ends of the plurality of the snake-shaped metal pipes and connected-and-communicative to both ends of the snake-shaped metal pipes so as to enclose around into an open loop making the working-fluid-flows flowing in the multi-pipe body mutually cross flows to increase the driving force in the multi-pipe body, thereby enhances the heat-dissipating effect as well as successfully overcomes the horizontal, negative angle, and low-temperature unable-to-start problems in the conventional pulsating multi-pipe heat pipe.

This application also claims priority to Taiwan Patent Application No. 103116564 filed in the Taiwan Patent Office on May 9, 2014, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The disclosure relates to a heat pipe for heat dissipating purpose, and more particularly, to a pulsating multi-pipe heat pipe to enclose an open-type loop by having independent chambered connectors furnished and communicated at both ends of a plurality of snake-shaped metal pipes respectively.

BACKGROUND

The heat pipe having good heat transfer performance is widely applied in electronic devices for heat-dissipating, especially personal computers, and notebook computers. In general, facing the heat-dissipating demands for the plane heat-generating mode, it is necessary to have the design of heat pipe by employing a number of heat pipes simultaneously to be able to satisfy the requirements of heat-dissipating. However, employing a number of heat pipes will result in the difficulties on heat-dissipating design as well as the assembly and manufacturing of heat-dissipating module. Two half frames the vapor chamber is a more suitable heat-dissipating device than the conventional heat pipe.

The difficulties for using vapor chamber having capillary action lies in the sintering fabrication of the capillary structure. The reasons are as follows:

-   1. The larger the vapor chamber, the harder it is to control the     uniformity of the capillary structure, thereby it is apt to result     in instability in performance; -   2. The larger the vapor chamber, the larger the sintering furnace is     needed which results in increasing the fabrication cost and lowering     the mass production speed; -   3. The strength of the pipe wall of the vapor chamber will be     substantially lower after annealing process is performed which     results in its inability to keep its required strength to respond to     the internal and external pressure variation.

Since the sintering process of the capillary structure can derive so many fabrication problems, a pulsating or oscillating heat pipe becomes another alternative for the vapor chamber.

The overall structure of the pulsating heat pipe nowadays is rather simple. The driving force of the pulsating heat pipe is an action generated by the heat pipe having relatively smaller pipe diameter, and by making use of the capillary action, gravitational force subjected to the working fluid, as well as the vapor pressure subjected to the absorbing heat However, since the capillary action of the conventional pulsating single-pipe heat pipe is very limited, the actuating force of the pulsating single-pipe heat pipe depends mainly on the gravitational force. For this reason, when it comes to the situation that the heat pipe is laid in horizontal position or is laid in negative-angle position, or in any skew positions where the heat-absorbing end is higher the heat-dissipating end, the conventional pulsating single-pipe heat pipe will not be able to be actuated.

SUMMARY

In view of the fact that the pulsating single-pipe heat pipe of the prior art is incapable of being actuated when it is laid in horizontal position or in the position when its heat-absorbing end is higher than the heat-dissipating end, the disclosure provides a pulsating multi-pipe heat pipe has its pipe bodies arranged in parallel and bent into a plurality of snake-shaped metal pipes, and an independent chamber is furnished respectively at both ends of the plurality of the snake-shaped metal pipes and connected-and-communicative to both ends of the snake-shaped metal pipes so as to enclose around into an open loop making the working-fluid-flows flowing in the multi-pipe body mutually cross flows to increase the driving force in the multi-pipe body, thereby enhances the heat-dissipating effect as well as successfully overcomes the horizontal, negative angle, and low-temperature unable-to-start problems in the conventional pulsating multi-pipe heat pipe.

Through the communicative mode of a plurality of metal pipes, when it comes to actuating, the pulsating multi-pipe heat pipe of the disclosure is capable of creating unbalanced volumetric filling quantity of working fluid, generating dynamic and alternate variation, and staying in unbalanced force for a long time for the working fluid contained in the metal pipes. Therefore, the pulsating multi-pipe heat pipe of the disclosure is capable of being started when it is laid in either horizontal or negative 90 degree angular positions (with heat-absorbing zone up and heat-dissipating zone down) or at low temperature condition to accomplish heat transfer effect.

The embodiments of the disclosure includes a plurality of snake-shaped loops having the same diameter and each having a plurality of chambered connectors to make the pulsating multi-pipe heat pipe of the disclosure become communicative.

The embodiments of the disclosure also includes a plurality of snake-shaped loops having different diameter and each having a plurality of chambered connectors to make the pulsating multi-pipe heat pipe of the disclosure become communicative.

BRIEF DESCRIPTION OF THE DRAWINGS

The accomplishment of this and other objects of the disclosure will become apparent from the following description and its accompanying drawings of which:

FIG. 1 is a plan view of a schematic drawing of the first embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 2A, 2B are a plan views of schematic drawings of the second embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 3 is a plan view of a schematic drawing of the third embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 4 is a plan view of a schematic drawing of the fourth embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 5 is a plan view of a schematic drawing of the fifth embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 6A, 6B are plan views of schematic drawings of the sixth embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 7 is a plan view of a schematic drawing of the seventh embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 8 is a plan view of a schematic drawing of the eighth embodiment of the pulsating multi-pipe heat pipe of the disclosure;

FIG. 9 is a comparing table of an operating characteristic when the heat pipe is laid in horizontal position of the pulsating multi-pipe heat pipe of the disclosure; and

FIG. 10 is a comparing table of an operating characteristic when the heat pipe is placed in negative 90 degree position of the pulsating multi-pipe heat pipe of the disclosure.

DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENT

FIG. 1 is a plan view of a schematic drawing of the first embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 1, the pulsating multi-pipe heat pipe (1) of the first embodiment of the disclosure is formed by having two in-parallel metal pipes (11), (12) with equal diameter placed side-by-side and bent into a plurality of snake-shaped loops (13) and each encloses an open system respectively. What is more, the pulsating multi-pipe heat pipe of the first embodiment (1) of the disclosure having two independent chambered connectors (14), (18) furnished to make the two metal pipes (11), (12) become communicative pulsating heat pipes with a partitioning plate (17) has a heat-absorbing area or a heat-dissipating area at a first end (15) and a heat-dissipating area or a heat-absorbing area at a second end. (16). The position of the chambered connectors (14), (18) is not limited to the heat-absorbing area. The position of the chambered connectors (14), (18) capable of locating at either the other positions of the pulsating multi-pipe heat pipe or on different sides of the position where the two metal pipes (11), (12) connected to the independent chambered connectors (14), (18) is within the scope of the disclosure.

FIG. 2A, 2B are a plan views of schematic drawings of the second embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in 2A, 2B and FIG. 1, besides having the two independent chambered connectors (24), (28) positioned at both ends of the metal pipes (21), (22) that are communicative to become pulsating multi-pipe heat pipe (2), the two independent chambered connectors (24), (28) are not within a same chamber and are furnished at the upper ends of the metal pipes (21), (22), and the remaining components has the same situation and are not depicted here.

FIG. 3 is a plan view of a schematic drawing of the third embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 3 and FIG. 1, besides having the two different-diameter metal pipes (31), (32) employ two independent chambered connectors (14), (18) respectively to make the two metal pipes (31), (32) communicative to become pulsating multi-pipe heat pipe (3), the remaining components has the same situation and are not depicted here.

FIG. 4 is a plan view of a schematic drawing of the fourth embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 4 and FIG. 2A, 2B, besides having the two different-diameter metal pipes (41), (42) employ two independent chambered connectors (24), (28) respectively to make the two metal pipes (41), (42) communicative to become pulsating multi-pipe heat pipe (4), the remaining components has the same situation and are not depicted here.

FIG. 5 is a plan view of a schematic drawing of the fifth embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 5 and FIG. 1, the pulsating multi-pipe heat pipe of the fifth embodiment of the disclosure is the same as that of the pulsating heat pipe as shown in FIG. 1 except that it employs three same diameter metal pipes (51), (52), (53) only that the employment of three different diameter metal pipes or two separate chambered connectors to communicate the three metal pipes is also within the scope of the disclosure.

FIG. 6A, 6B are plan views of schematic drawings of the sixth embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in 6A, 6B and FIG. 2A, 2B, the pulsating multi-pipe heat pipe of the sixth embodiment of the disclosure is the same as that of the pulsating heat pipe as shown in FIG. 2A, 2B except that it employs three same diameter metal pipes (61), (62), (63) only that the employment of three different diameter metal pipes is also within the scope of the disclosure.

FIG. 7 is a plan view of a schematic drawing of the seventh embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 7, the seventh embodiment of the pulsating multi-pipe heat pipe of the disclosure is formed by two metal pipes (71), (72) having different size of pipe diameter. An end of each of the metal pipes a plurality of snake-shaped loops (73), (74) enclosing an open-type system respectively and positioning at an end of a pulsating multi-pipe heat pipe (7) while employing two independent chambered connectors (14), (18) to make the pulsating multi-pipe heat pipe (7) become communicative. Among them, the metal pipes (71), (72) being non-parallel are positioned at both ends of the two independent chambered connectors (14), (18), and the two independent chambered connectors (14), (18) are not in the same chamber. The heat absorbing zone (75) (can also be the heat dissipating zone) is in the mid part of the pulsating multi-pipe heat pipe (7) while the heat dissipating zones (76), (77) (can also be the heat absorbing zones) are at the ends of the plurality of snake-shaped loops (73), (74), but using same pipe diameter is also within the scope of the disclosure.

FIG. 8 is a plan view of a schematic drawing of the eighth embodiment of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 8 and FIG. 7, besides having the two independent chambered connectors (24), (28) be disposed at both ends of the metal pipes (81), (82) respectively to be communicative to form pulsating multi-pipe heat pipe (8), the two independent chambered connectors (24), (28) are not in the same chambered connectors but are disposed at both ends of the metal pipes (81), (82), but using same pipe diameter is also within the scope of the disclosure.

The above-mentioned working fluid in the pulsating multi-pipe heat pipe is filled in through an inlet opening, and after the filling work is done, the inlet opening is sealed. The working fluid filling rate of the pulsating multi-pipe heat pipe is 30˜80% (volumetric ratio). This is the ratio of the volume of the working fluid filled in the heat pipe to the total volume of the heat pipe when it is not filled with working fluid. The air in the heat pipe is totally vacuumed through the inlet opening before the working fluid is filled. This kind of working fluid filling method is the same for all the above-mentioned embodiments of the disclosure.

The double hatch lines in different directions in metal pipes (11), (12) as shown in FIG. 1 as well as those shown in FIG. 2 a, FIG. 2B, FIG. 3˜FIG. 8 are for differentiating purpose and not for showing the cross section of the pipes.

The above-mentioned communicating method between the two independent chambered connectors (14), (18) and the metal pipes is to communicate the two pulsating heat pipes to form one structure of pulsating heat pipe. First of all, a round hole is drilled on each end part of the two independent chambered connectors (14), (18) and both end of the metal pipes are plugged into the two independent chambered connectors (14), (18) and welded to connect. If D is the diameter of the metal pipes (11), (12) and W, H, L1 are the width (not shown in the Figure), height, and length of the chambered connectors (14), (18), then it is preferable that W or H is less than 10D, and 2 D≦L1≦20 D. This is because that there are at least two metal pipes, and the bigger the volume of the chambered connectors (14), (18), the harder it is for the capillary action to be controlled and apt to be unstable. Since the length of the chambered connectors (14), (18) does not affect so much on the disposition of the dissipating module, the length can be relatively larger than the width or the height. The pipe diameter is preferable between 0.1 mm and 8.0 mm. The diameter of the pipe needs at least 0.1 mm since it is not easy to make the pipe if the diameter is too small. On the other hand, the diameter of the pipe needs to be no more than 8.0 mm since the capillary action will be worse if the diameter is too large. As shown in FIG. 1, as the heat-absorbing zone (15) of the pulsating multi-pipe heat pipe (1) is heated, the working fluid will be evaporated and its vapor pressure is increased to push the working fluid to flow. As shown further in FIG. 1, the working fluid with high temperature and high vapor pressure will flow toward the heat-dissipating zone (16), that is to say, the heat is sent from the heat-absorbing zone (15) with high temperature toward the heat-dissipating zone (16) with low temperature to achieve the heat transfer effect. In this way, the pressure difference generated by the metal pipes (11), (12) is greater that that of the single pipe. As shown in FIG. 2A, the pressure generated by the working fluid in the metal pipes (21) communicative to the independent chambered connectors (24) is greater than the pressure generated by the working fluid in the metal pipes (22) making the working fluid within the left-most metal pipes (21) flow upward and the working fluid within the left-most metal pipes (22) flow downward. The flow directions of the working fluid within the plurality of snake-shaped metal pipes (22) are shown as the arrow heads.

As shown in FIG. 2B, the pressure generated by the working fluid in the metal pipes (21) communicative to the independent chambered connectors (24) is smaller than the pressure generated by the working fluid in the metal pipes (22) making the working fluid within the left-most metal pipes (21) flow downward and the working fluid within the left-most metal pipes (22) flow upward. The flow directions of the working fluid within the plurality of snake-shaped metal pipes (22) are shown as the arrow heads. As one can see that the flow direction of the working fluid shown in FIG. 2B is adverse to that of the one shown in FIG. 2A.

Referring again to FIG. 6A, the pressure generated by the working fluid in the metal pipes (61) communicative to the independent chambered connectors (24) is greater than the pressure generated by the working fluid in the metal pipes (62), (63) making the working fluid within the left-most metal pipes (61) flow upward and the working fluid within the left-most metal pipes (21) flow downward. The flow directions of the working fluid within the plurality of snake-shaped metal pipes (62), (63) are shown as the arrow heads.

Referring again to FIG. 6B, the pressure generated by the working fluid in the metal pipes (61) communicative to the independent chambered connectors (24) is smaller than the pressure generated by the working fluid in the metal pipes (62), (63) making the working fluid within the left-most metal pipes (61) flow downward and the working fluid within the left-most metal pipes (62), (63) flow upward. The flow directions of the working fluid within the plurality of snake-shaped metal pipes (62), (63) are shown as the arrow heads with flow direction of the working fluid opposite to that of the one in FIG. 6A causing the working fluid within the pulsating multi-pipe heat pipe (1)˜(8) cross flow, thereby making the fluid distributes in random manner to form non-uniform filling volume and generate unbalance force. In this way, it is capable of successfully overcoming the starting problem of the pulsating multi-pipe heat pipe making it possible to operate in negative 90 degree status (i.e. heat-dissipating zone up and heat-absorbing zone down) and making it capable to operate even if it lacks of the aid of gravitational force to let the working fluid flow back to the heat-dissipating zone. The communicative mode and the cross flowing principle of the working fluid is the same for the rest of above-mentioned seven embodiments.

Experimental Embodiment

In the experimental embodiment, an open type pulsating multi-pipe heat pipe of the disclosure and a closed type pulsating multi-pipe heat pipe are fabricated by the structure of the embodiment of FIG. 1. First of all, both types of pulsating multi-pipe heat pipes are vacuumized and filled with working fluid by 60% of the total volume of the flowing channel of the piping system. Subsequently, heat Q_(in) is added to both types of pulsating multi-pipe heat pipes, and in the same time, the disposition of the heat pipes is varied with different orientation angle to measure the temperature of the heat-absorbing zone (T_(H)) and the heat-dissipating zone (T_(L)). By the following formula R_(th)=(T_(H)−T_(L))/Q_(in) where R_(th) is the thermal resistance, it is understood that the smaller the temperature difference (T_(H)−T_(L)), the smaller the thermal resistance it is. Further more, in a formula:

Q _(out)=(m/t)×(Cp)×(Tin−Tout)

where Q_(out) is the heat carried away by the working fluid in the heat-dissipating zone, (m/t) is the mass flow rate in Kg/S, (Cp) is the specific heat in J/Kg-° C. of the working fluid in heat-dissipating zone while (T_(in)−T_(out)) is the inlet-outlet temperature difference of the working fluid in heat-dissipating zone. It is understood that the larger the Q_(out), the better efficiency of the pulsating multi-pipe heat pipe it is.

In every operating angles, the performances of varies pulsating multi-pipe heat pipes are compared by calculating the heat Q_(out) carried away by the working fluid in the heat-dissipating zone and the temperatures T_(H) of the heat-absorbing zone and T_(L) of the heat-dissipating zone. FIG. 9 is a comparing table of an operating characteristic when the heat pipe is laid in horizontal position of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 9, the left-handed and right-handed charts are the comparison of the horizontal operating performance between the application Ser. No. 10/213,1568 of the applicant and the disclosure wherein Q_(out) is the heat carried away by the working fluid in the heat-dissipating zone and ΔT is the temperatures difference of the heat-absorbing zone T_(H) and the heat-dissipating zone T_(L) while T_(avg,h) is the average temperature of the heat-absorbing zone. It is understood that the closed-type pulsating multi-pipe heat pipe is unable to start at low temperature (45° C.) when T_(avg,h)=45° C. However, the open-type pulsating multi-pipe heat pipe of the disclosure can be started at at low temperature (45° C.) with Q_(out)=35W and ΔT=7° C. FIG. 10 is a comparing table of an operating characteristic when the heat pipe is placed in negative 90 degree position of the pulsating multi-pipe heat pipe of the disclosure. As shown in FIG. 10, the left-handed and right-handed charts are the comparison of the negative 90-degree angle operating performance between the application Ser. No. 10/213,1568(TW) of the applicant and the disclosure. It is understood that the closed-type pulsating multi-pipe heat pipe is unable to start at low temperature (45° C.). However, the open-type pulsating multi-pipe heat pipe of the disclosure can be started at at low temperature (45° C.) with Q_(out)=28W and ΔT=4° C.

To summarize the above-mentioned description, when it comes to action, the pulsating multi-pipe heat pipe of the disclosure is capable of creating unbalanced volumetric filling quantity of working fluid, generating dynamic and alternate variation, and staying in unbalanced force for a long time for the working fluid contained in the metal pipes. Therefore, the pulsating multi-pipe heat pipe of the disclosure is capable of being started when it is laid in either horizontal or negative 90 degree angular positions (with heat-absorbing zone up and heat-dissipating zone down) or at low temperature condition to accomplish heat transfer effect.

It will become apparent to those people skilled in the art that various modifications and variations can be made to the structure of the disclosure without departing from the scope or spirit of the disclosure. In view of the foregoing description, it is intended that all the modifications and variation fall within the scope of the following appended claims and their equivalents. 

What is claimed is:
 1. A pulsating multi-pipe heat pipe, comprising: at least two independent metal pipes having a plurality of snake-shaped loops respectively, and the two metal pipes are in parallel; and at least two independent chambered connectors to be connected to both ends of each of the at least two metal pipes.
 2. The pulsating multi-pipe heat pipe in claim 1, wherein the diameters of the at least two metal pipes are equal.
 3. The pulsating multi-pipe heat pipe in claim 1, wherein the diameters of the at least two metal pipes are unequal.
 4. The pulsating multi-pipe heat pipe in claim 1, wherein the dimension of the diameter of the metal pipes is in the range of 0.1˜8.0 mm.
 5. The pulsating multi-pipe heat pipe in claim 1, wherein both the dimensions of the width and height of the independent chambered connector not in the same chamber are in the range of 2D˜10D while the length of which is in the range of 2D˜20D where D being the diameter of the metal pipes.
 6. The pulsating multi-pipe heat pipe in claim 1, wherein the two independent chambered connectors are within a chamber employing a partition plate to form two independent chambers.
 7. The pulsating multi-pipe heat pipe in claim 1, wherein the two independent chambered connectors are not within a chamber and are furnished at the upper ends of the two independent metal pipes respectively.
 8. The pulsating multi-pipe heat pipe in claim 1, wherein the at least two pulsating multi-pipe heat pipes are filled with working fluid that is capable of being operated either in horizontal and or in negative 90° positions or at low temperature condition when the working fluid is subjected to be heated.
 9. The pulsating multi-pipe heat pipe in claim 1, wherein the filling rate of the working fluid within the at least two metal pipe is in a range of 30˜80% (volumetric ratio).
 10. The pulsating multi-pipe heat pipe in claim 1, wherein a heat-absorbing end is at one end and a heat-dissipating end is at the other end of the at least two metal pipes.
 11. A pulsating multi-pipe heat pipe, comprising: at least two independent metal pipes having a plurality of snake-shaped loops respectively; and at least two independent chambered connectors to be connected to both ends of each of the at least two metal pipes wherein the metal pipes are positioned at both ends of the chambered connectors and are not in parallel.
 12. The pulsating multi-pipe heat pipe in claim 11, wherein the diameters of the at least two metal pipes are equal.
 13. The pulsating multi-pipe heat pipe in claim 11, wherein the diameters of the at least two metal pipes are unequal.
 14. The pulsating multi-pipe heat pipe in claim 11, wherein the dimension of the diameter of the metal pipes is in the range of 0.1˜8.0 mm.
 15. The pulsating multi-pipe heat pipe in claim 11, wherein both the dimensions of the width and height of the independent chambered connector not in the same chamber are in the range of 2D˜10D while the length of which is in the range of 2D˜20D where D being the diameter of the metal pipes.
 16. The pulsating multi-pipe heat pipe in claim 11, wherein the two independent chambered connectors are within a chamber employing a partition plate to form two independent chambers.
 17. The pulsating multi-pipe heat pipe in claim 11, wherein the two independent chambered connectors are not within a chamber and are furnished at the upper ends of the two independent metal pipes respectively.
 18. The pulsating multi-pipe heat pipe in claim 11, wherein the at least two pulsating multi-pipe heat pipes are filled with working fluid that is capable of being operated either in horizontal and or in negative 90° positions or at low temperature condition when the working fluid is subjected to be heated.
 19. The pulsating multi-pipe heat pipe in claim 11, wherein the filling rate of the working fluid within the at least two metal pipe is in a range of 30˜80% (volumetric ratio).
 20. The pulsating multi-pipe heat pipe in claim 11, wherein a heat-absorbing end is at one end and a heat-dissipating end is at the other end of the at least two metal pipes. 